staging: comedi: das08: rename DAS08AO_AO_UPDATE
authorIan Abbott <abbotti@mev.co.uk>
Fri, 5 Jun 2015 17:30:25 +0000 (18:30 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 13 Jun 2015 00:06:41 +0000 (17:06 -0700)
commit6814b4a3fd3867d4104eecc371f73beced6cb499
tree25ee0871b62b25e621cc9caec41487208020dc28
parent3c98c1d3f1d3912738dca864fd00910654ed2a65
staging: comedi: das08: rename DAS08AO_AO_UPDATE

"AOL", "AOM", and "AOH" boards have a jumper that controls whether
analog output channels are updated simultaneously or individually.  When
set to update individually, individual channels are updated when the
high byte register is written.  When set to update simultaneously,
channels are not updated until any of the analog output registers are
read.  The driver doesn't know the jumper setting and is not interested
in the simultaneous update feature, so it updates a channel by writing
the low byte register, the high byte register, and then reading channel
0's low byte register.

The `DAS08AO_AO_UPDATE` macro contains the offset to the low byte
register for analog output channel 0 on the "AOL", "AOM", and "AOH"
boards, which the driver reads to update the analog outputs.  Rename the
macro to `DAS08AOX_AO_UPDATE_REG` and add a comment.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/comedi/drivers/das08.c